A noise-reducing impeller and a fluid conveyor having the impeller

Abstract

The present invention discloses a noise-reducing impeller and a fluid conveyor having the impeller. The noise-reducing impeller includes blades and a substrate. The blades are arranged on the substrate, and the edges of the blades are flush with the outer periphery of the substrate. It is characterized in that the interval angle between each group of adjacent blades is different from the interval angle between any other adjacent blades; the fluid conveyor includes a volute for cooperating with the noise-reducing impeller. The volute is successively divided into a tongue section, a diffuser section, and an outlet section along the fluid conveying direction. The diffuser section and the outlet section adopt a flaring structure with a uniformly increasing cross-section. By the blades non-uniformly distributed on the substrate, the present invention effectively eliminates the fundamental frequency harmonics during the high-speed rotation of the impeller, and at the same time can reduce the aerodynamic noise caused by turbulent gas and wake vortices; the tongue section effectively reduces the pressure pulsation of the fluid, the static pressure distribution in the diffuser section is more uniform, the pressure gradient is smaller, the vortices and secondary flows are reduced, thereby reducing the exhaust gas flow noise.

Description

Technical Field

[0001] The present invention relates to the technical field of centrifugal fans, and particularly to a noise-reducing impeller and a fluid conveyor having the impeller. Background Art

[0002] High-speed rotating machinery such as high-speed centrifugal fans and air compressors are widely used in the industrial field. The aerodynamic noise of the high-speed rotating fluid mainly originates from the injection, wake vortex excited by the contact between the rotating blade and the air flow, and their interaction with the volute tongue and between the blades. Among them, the eddy current noise is an aerodynamic noise generated by the separation of the boundary layer on the flow-through surface of the blades of the centrifugal fluid component, which causes the air flow pressure pulsation.

[0003] Due to the high rotational speed, wide noise frequency band, and high noise level of conventional fluid components, there are noise pollution problems in practical applications. Due to the intake and exhaust pulsation noise and the main engine rotation noise, which present broadband characteristics, the noise of the whole machine is higher than the industrial noise limit value.

[0004] Existing fluid components are based on high efficiency. Conventional regular blade fluid components result in relatively high high-frequency noise, relatively high vortex noise and aerodynamic noise of high-speed rotating fluid components. The regular blades rotating periodically make the noise present high-frequency characteristics, and the flow velocity state at the volute tongue outlet is not good, causing severe pressure pulsation, which further aggravates the outlet radiation noise level. Summary of the Invention

[0005] Technical Objective: Aiming at the deficiencies of the existing impeller structure with regular blades having high noise levels, high frequencies, and large noise in intake and exhaust, the present invention discloses a noise-reducing impeller that can effectively reduce the air flow noise at the volute outlet and a fluid conveyor having the impeller.

[0006] Technical Solution: To achieve the above technical objective, the present invention adopts the following technical solution:

[0007] A noise-reducing impeller includes blades and a base plate. The blades are arranged on the base plate, and the edges of the blades are flush with the outer periphery of the base plate. It is characterized in that the interval angle between each group of adjacent blades is different from the interval angle between any other adjacent blades.

[0008] Preferably, the interval angle of the blades follows the dynamic balance constraint equation where N represents the total number of blades, θ i ′ represents the circumferential angle of the blade corresponding to the i-th impeller, 2 ≤ i ≤ N.

[0009] Preferably, a bionic serrated noise reduction structure is provided at the end of the blade.

[0010] Preferably, the tooth width, tooth pitch, and tooth height of the bionic serrated noise reduction structure are enlarged in proportion according to the ratio of the corresponding blade to the reference bionic noise reduction blade.

[0011] The present invention also provides a fluid conveyor, which uses the above noise-reducing impeller for fluid conveyance.

[0012] Preferably, the fluid conveyor includes a volute for cooperating with the noise-reducing impeller. The volute is sequentially divided into a tongue section, a diffuser section, and an outlet section along the fluid conveyance direction. The diffuser section and the outlet section adopt a flared structure with a uniformly increasing cross-section. In the tongue section, the cross-sectional area of the volute In the diffuser section and the outlet section, the cross-sectional area of the volute Among them, is the circumferential angle of the cross-section relative to the cross-section where the fluid enters the volute. X ranges from 30° to 60°, f is the blade rotation frequency, and b is the noise-reducing cross-section coefficient. Among them, ρ represents the fluid density, with the unit of kg / m 3 ; μ is the cross-section correction coefficient to ensure the exhaust gas volume, with a value range of 1.2 to 4.2, P1 is the gas pressure in the outlet section, a is the proportionality coefficient of the volute cross-section determined according to the impeller used in the volute, s represents the interval of the non-smooth units in the tongue section, with a value of 100 - 200 mm, and h is the height of the non-smooth units in the tongue section, with a value of 5 - 20 mm.

[0013] Beneficial effects: A noise-reducing impeller provided by the present invention and a fluid conveyor having the impeller have the following beneficial effects:

[0014] 1. By the blades non-uniformly distributed on the substrate, the present invention effectively eliminates the fundamental frequency harmonics during the high-speed rotation of the impeller and can simultaneously reduce the aerodynamic noise caused by turbulent gas and wake vortices.

[0015] 2. The volute of the present invention is divided into a tongue section, a diffuser section, and an outlet section along the air flow direction. The tongue section effectively reduces the pressure pulsation of the fluid. In the diffuser section, the static pressure distribution is more uniform, the pressure gradient is smaller, the vortices and secondary flows are reduced, thereby reducing the exhaust gas flow noise. Description of the Drawings

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art.

[0017] Figure 1 It is a structural diagram of the noise-reducing impeller of the present invention;

[0018] Figure 2 It is a structural diagram of the fluid conveyor of the present invention;

[0019] Figure 3 It is a structural diagram of the volute of the present invention;

[0020] Figure 4 It is a partial structural diagram of the tongue section of the volute of the present invention;

[0021] Figure 5 This is a comparison chart of the pneumatic noise levels between the fluid conveyor of the present invention and conventional fluid components;

[0022] Among them, 1 - blade, 2 - substrate, 3 - bionic serrated noise reduction structure, 4 - volute, 5 - tongue section, 6 - diffuser section, 7 - outlet section. Specific embodiments

[0023] The present invention will be more clearly and completely described below by way of a preferred embodiment in conjunction with the accompanying drawings, but the present invention is not limited to the scope of the described embodiments.

[0024] As Figure 1 shown, a noise reduction impeller disclosed by the present invention includes a blade 1 and a substrate 2. The blades 1 are arranged on the substrate 2, and the edges of the blades 1 are flush with the outer periphery of the substrate 2. It is characterized in that the interval angle between each group of adjacent blades is different from that between any other adjacent blades.

[0025] Specifically, first, according to the number of blades 1 to be installed on the substrate 2, the blades are arranged in a uniformly distributed manner. For long and short blades, they can be arranged at uniform intervals, and then each blade is adjusted by an angle to one side based on the uniformly distributed position to ensure that the interval angles between each group of adjacent blades are all different; at the same time, in order to ensure that the noise reduction impeller can maintain the dynamic balance performance requirements and aerodynamic performance requirements during rotation, the interval angles of the blades 1 of the present invention comply with the dynamic balance constraint equation where N represents the total number of blades, and θ′ i represents the circumferential angle of the blade corresponding to the i-th impeller, 2 ≤ i ≤ N.

[0026] Taking a noise reduction impeller with 8 groups of blades as an example, the impeller structure provided by the present invention will be specifically described. Each blade is distributed on the substrate in a uniformly arranged manner, and the interval angle between the blades is 45°. To ensure that the interval angles between the impellers are inconsistent, the impellers are numbered in the order of 1 - 8, and the impellers are adjusted by angles in turn: -5° to -1°, +1° to +3°, -8° to -4°, +1° to +4°, +3° to +7, -4° to -1°, -6° to -2°, +3° to +8°; and the arrangement of the blades is made to meet the requirements of dynamic balance and aerodynamic performance. The specific adjustment angles can be specifically determined by modeling and simulation tests in simulation software.

[0027] At the same time, the noise reduction impeller of the present invention is provided with a bionic serrated noise reduction structure 3 at the end of the blade 1. The tooth width, tooth pitch, and tooth height of the bionic serrated noise reduction structure 3 are enlarged in proportion according to the ratio of the corresponding blade to the reference bionic noise reduction blade to ensure its noise reduction effect.

[0028] For the bionic blade noise reduction structure at the blade tip, the calculation shall be carried out according to the following table:

[0029] Table of Bionic Blade Serrated Structure Parameters

[0030] Structure parameter Area s Tooth width d Pitch e Tooth height f Parameter unit <![CDATA[mm 2 > mm mm mm Reference blade 1 44.4-55.6 0.3-0.7 0.2-0.8 0.4-1.2 Specific value 1.85×24 0.4 0.6 0.8 Long blade 2325.97 2.2-5.04 1.44-5.76 2.88-8.64 Specific value 13.39×173.7l 2.2 3.3 4.4 Reference blade 2 55.9-65.9 0.3-0.7 0.2-0.8 0.4-1.2 Specific value 2.33×24 0.4 0.6 0.8 Short blade 1846.21 1.7-3.99 1.14-4.56 2.28-6.84 Specific value 13.39×137.88 1.8 2.7 3.6

[0031] Among them, reference blade 1 is the benchmark blade size corresponding to the long blade on the impeller, and reference blade 2 is the benchmark blade size corresponding to the short blade on the impeller. From the proportional relationship between the corresponding blade and the benchmark blade, the size of the bionic serrated noise reduction structure at the blade edge can be obtained. The areas of the long blade and the short blade in the table are the blade areas designed in the embodiment to meet the corresponding aerodynamic performance requirements.

[0032] As Figure 2 - Figure 4 shown, the present invention also provides a fluid conveyor with the above-mentioned noise reduction impeller. The fluid conveyor includes a volute 4 for cooperating with the noise reduction impeller. The volute 4 is successively divided into a tongue segment 5, a diffuser segment 6, and an outlet segment 7 along the fluid conveying direction. The diffuser segment 6 and the outlet segment 7 adopt a flaring structure with a uniformly increasing cross-section. In the tongue segment 6, the cross-section of the volute moves In the diffuser segment 6 and the outlet segment 7, the cross-section of the volute moves Among them, The circumferential angle of the hook cross-section relative to the cross-section where the fluid enters the volute, X ranges from 30° to 60°, f is the blade rotation frequency, and b is the noise reduction cross-section coefficient. Among them, ρ represents the fluid density, with the unit of kg / m 3 ; μ is the cross-section correction coefficient to ensure the exhaust volume, with the value range of 1.2 to 4.2, P1 is the gas pressure at the outlet segment, a is the proportionality coefficient of the volute cross-section determined according to the impeller used in the volute, s represents the interval of the non-smooth unit in the tongue segment, with the value of 100 - 200 mm, and h is the height of the non-smooth unit in the tongue segment, with the value of 5 - 20 mm.

[0033] As Figure 5 shown, at the rated speed of 24000 r / min, the aerodynamic noise level test is carried out. The solid line represents the test result of the conventional fluid component, and the dashed line represents the noise test result of the fluid conveyor using the present invention. By means of the noise reduction impeller structure and the fluid conveyor of the present invention, the fundamental frequency harmonics of the high-speed rotating impeller and the pressure pulsation of the fluid in the volute can be significantly reduced, achieving the purpose of reducing the operating noise.

[0034] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A fluid conveyor, characterized in that, It includes a volute (4) for cooperating with a noise-reducing impeller. The noise-reducing impeller includes blades (1) and a base plate (2). The blades (1) are arranged on the base plate (2), and the edges of the blades (1) are flush with the outer periphery of the base plate (2). The interval angle between each group of adjacent blades is different from that between any other adjacent blades. The volute (4) is sequentially divided into a tongue section (5), a diffuser section (6), and an outlet section (7) along the fluid conveying direction. The diffuser section (6) and the outlet section (7) adopt a flared structure with a uniformly increasing cross-section. In the tongue section (5), the cross-sectional area of the volute ; in the diffuser section (6) and the outlet section (7), the cross-sectional area of the volute , where is the circumferential angle of the cross-section relative to the cross-section where the fluid enters the volute, X ranges from 30° to 60°, f is the blade rotation frequency, b is the noise-reducing cross-section coefficient, ; where ρ represents the fluid density, with the unit of kg / m 3 ; μ is the cross-section correction coefficient to ensure the exhaust gas volume, and its value range is 1.2 to 4.2, is the gas pressure in the outlet section, is the proportionality coefficient of the volute cross-section determined according to the impeller used in the volute, s represents the interval of the non-smooth units in the tongue section, with a value of 100 - 200 mm, and h is the height of the non-smooth units in the tongue section, with a value of 5 - 20 mm.

2. A fluid conveyor according to claim 1, characterized in that, The interval angle of the blade (1) follows the dynamic balance constraint equation , where N represents the total number of blades, represents the circumferential angle of the blade corresponding to the i-th impeller, and 2 ≤ i ≤ N.

3. A fluid conveyor according to claim 1, characterized in that, A bionic serrated noise reduction structure (3) is provided at the end of the blade (1).

4. A fluid conveyor according to claim 3, characterized in that The tooth width, tooth pitch and tooth height of the bionic serrated noise reduction structure (3) are enlarged in proportion according to the ratio of the corresponding blade to the reference bionic noise reduction blade.

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